The present disclosure relates generally to methods of immobilizing dyes and antimicrobial agents on a surface, especially a surface of a medical device. In particular, the disclosure relates to methods of treating a polymer surface for better attachment of antimicrobial agents onto the surface, and for the attachment of dyes to the surface. The dyes will change from a first color or appearance to a second color or appearance when they are swabbed with a disinfecting fluid, such as isopropyl alcohol (IPA) or a solution of water and IPA, especially a solution of 70% water/30% IPA.
Infections acquired at hospitals or other health care sites, nosocomial infections, are an undesirable source of distress to patients. The advent of ever-more resistant bacteria and bacteria that are resistant to multiplicities of drugs only exacerabates the problem and makes the eradication of these infections even more important. An example of one cause of such infections is a biofilm, an aggregate of microbes with a distinct architecture. A biofilm is similar to a small city with a great abundance of microbial cells, each only a micrometer or two in length. The microbes form towers that can be hundreds of micrometers high, with the “streets” between the towers being fluid filled channels that supply nutrients, oxygen, and other necessities to the biofilm communities.
Such biofilms can form on the surfaces of medical devices, especially implants, such as contact lenses, catheters or other access devices, pacemakers, and other surgical implants. The U.S. Centers for Disease Control (CDC) estimates that over 65% of nosocomial infections are caused by biofilms. Bacteria growing in a biofilm can be highly resistant to antibiotics, up to a thousand times more resistant than the same bacterium not growing in a biofilm. It would be desirable if the surfaces of these medical devices were resistant to biofilm formation and bacterial growth.
Polymers are used to make many of the diagnostic or therapeutic medical devices that are subject to biofilm formation. For example, connectors for kidney dialysis, such as peritoneal dialysis and hemodialysis may be made of polymers. Dialysate fluid containers, access ports, pigtail connectors, spikes, and so forth, are all made from plastics or elastomers. Therapeutic devices such as catheters, drug vial spikes, vascular access devices such as luer access devices, prosthetics, and infusion pumps, are made from polymers. Medical fluid access devices are commonly used in association with medical fluid containers and medical fluid flow systems that are connected to patients or other subjects undergoing diagnostic, therapeutic or other medical procedures. Other diagnostic devices made from polymers, or with significant polymer content meant for contact with tissues of a patient, include stethoscopes, endoscopes, bronchoscopes, and the like. It is important that these devices be sterile when they are to be used in intimate contact with a patient.
Typical of these devices is a vascular access device that allows for the introduction of medication, antibiotics, chemotherapeutic agents, or a myriad of other fluids, to a previously established IV fluid flow system. Alternatively, the access device may be used for withdrawing fluid from the subject for testing or other purposes. The presence of one or more access devices in the IV tubing sets eliminates the need for phlebotomizing the subject repeatedly and allows for immediate administration of medication or other fluids directly into the subject.
Several different types of access devices are well known in the medical field. Although varying in the details of their construction, these devices usually include an access site for introduction or withdrawal of medical fluids through the access device. For instance, such devices can include a housing that defines an access opening for the introduction or withdrawal of medical fluids through the housing, and a resilient valve member or gland that normally closes the access site. Beyond those common features, the design of access sites varies considerably. For example, the valve member may be a solid rubber or latex septum or be made of other elastomeric material that is pierceable by a needle, so that fluid can be injected into or withdrawn from the access device. Alternatively, the valve member may comprise a septum or the like with a preformed but normally closed aperture or slit that is adapted to receive a specially designed blunt cannula therethrough. Other types of access devices are designed for use with connecting apparatus employing standard male luers. Such an access device is commonly referred to as a “luer access device” or “luer-activated device,” or “LAD.” LADS of various forms or designs are illustrated in U.S. Pat. Nos. 6,682,509, 6,669,681, 6,039,302, 5,782,816, 5,730,418, 5,360,413, and 5,242,432, and U.S. Patent Application Publications Nos. 2003/0208165 and 2003/0141477, all of which are hereby incorporated by reference herein.
Before an access device is actually used to introduce or withdraw liquid from a container or a medical fluid flow system or other structure or system, good medical practice dictates that the access site and surrounding area be contacted, usually by wiping or swabbing, with a disinfectant or sterilizing agent such as isopropyl alcohol or the like to reduce the potential for contaminating the fluid flow path and harming the patient. It will be appreciated that a medical fluid flow system, such as an IV administration set, provides a direct avenue into a patient's vascular system. Without proper aseptic techniques by the physician, nurse or other clinician, microbes, bacteria or other pathogens found on the surface of the access device could be introduced into the IV tubing and thus into the patient when fluid is introduced into or withdrawn through the access device. Accordingly, care is required to assure that proper aseptic techniques are used by the healthcare practitioner. This warning applies to many medical devices, especially those in contact with the patient, and especially so for access devices that, like catheters or infusion pumps, access the patient's bodily orifices, especially those of the vascular system. Other devices that are subject to multiple touches include device covers and housings, and especially touch-screens, key pads, and user controls, such as switches, handles, and knobs.
As described more fully below, the methods for attaching antimicrobial agents and dyes that indicate that proper aseptic techniques have been used, are believed to represent important advances in the safe and efficient administration of health care to patients.